JP4299480B2 - Metal wire manufacturing method and metal cord using the metal wire - Google Patents

Description

【００４１】
【表２】

【００４２】
【発明の効果】
本発明は叙上の如く構成しているため、３元合金メッキを用いた場合にも、伸線加工性の低下を防止でき、有機酸コバルト塩などの使用を減じる或いは排除しながら、優れた初期接着性や湿熱接着性を発揮しうるとともに、伸線加工性を向上させうる。
【図面の簡単な説明】
【図１】本発明の金属ワイヤの製造方法を概念的に説明する工程図である。
【図２】一次の３元合金メッキ層の形成工程を説明する線図である。
【図３】一次の３元合金メッキ層の外側に形成される銅メッキ層を示す断面図である。
【図４】伸線加工を示す断面図である。
【図５】伸線加工による熱拡散における銅の分布状況を示す線図である。
【符号の説明】
２ 金属ワイヤ
３ 一次の３元合金メッキ層
３Ａ 銅メッキ層
３Ｂ 亜鉛メッキ層
３Ｃ ニッケルメッキ層
４ 外側の銅メッキ層
５ ダイス
６ 二次の３元合金メッキ層[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a metal wire manufacturing method capable of improving wire drawing workability while ensuring high rubber adhesion in a humid heat environment, and a metal cord using the metal wire.
[0002]
[Prior art]
Metal cords are often used as reinforcement elements for rubber products from the standpoint of high cord strength and excellent reinforcement effect.For example, in pneumatic tires, carcasses and belt layers of large tires, tires for passenger cars, and the like are also used. It is used as a reinforcing element such as a belt layer.
[0003]
Conventionally, this metal cord is subjected to brass plating or the like on the metal cord side in order to enhance adhesion to rubber, and a large amount of organic acid cobalt salt or the like is blended in the rubber on the rubber side. is doing.
[0004]
Here, the copper in the brass plating is highly reactive with sulfur in the rubber during vulcanization, and zinc moderately reduces the reactivity of copper with respect to sulfur. As a result, it is considered that an appropriate sulfide is generated at the interface between the plating surface of the metal wire and the rubber, and strong adhesion to the rubber can be obtained.
[0005]
However, the metal wire with a brass plating layer has low heat and high humidity, such as low adhesiveness in high-temperature and high-humidity environments, even when good adhesion is obtained by vulcanization. It tends to be inferior in adhesion. Therefore, conventionally, the organic acid cobalt salt or the like is blended in the rubber.
[0006]
However, although the organic acid cobalt salt is effective for wet heat adhesion after vulcanization, the unvulcanized rubber is easily deteriorated and heat-aged, and rubber products are formed with such deteriorated unvulcanized rubber. In this case, there is a problem that desired initial adhesiveness, wet heat adhesiveness, or rubber physical properties cannot be exhibited. Moreover, the organic acid cobalt salt is very expensive and disadvantageous in terms of cost.
[0007]
Therefore, in recent years, it has been proposed to perform ternary alloy plating made of copper, zinc and nickel instead of the brass plating. This ternary alloy plating has the advantage that excellent initial adhesion and wet heat adhesion can be exhibited while reducing or eliminating the use of organic acid cobalt salts and the like.
[0008]
[Problems to be solved by the invention]
However, the ternary alloy plating has low plastic deformation ability such as inferior ductility. Therefore, there is a problem that the wire drawing resistance increases when wire drawing is performed on a metal wire, and the wire drawing workability is impaired.
[0009]
Therefore, the present invention can prevent deterioration of wire drawing workability even when ternary alloy plating is used, and has excellent initial adhesiveness and wet heat adhesiveness while reducing or eliminating the use of organic acid cobalt salt and the like. An object of the present invention is to provide a method of manufacturing a metal wire that can be exhibited and improve wire drawing workability, and a metal cord using the metal wire.
[0010]
[Means for Solving the Problems]
In order to achieve the above object, the invention of claim 1 of the present application is based on the fact that a plating layer made of copper, zinc and nickel is thermally diffused on the surface of a metal wire so that the average composition is 60 to 75% by weight of copper and nickel 4 Forming a primary ternary alloy plating layer of -14 wt% ;
And forming a copper plating layer outside the primary ternary alloy plating layer,
The metal wire on which the outer copper plating layer is formed is pulled out with a die, and a secondary ternary is formed by the primary ternary alloy plating layer and the outer copper plating layer facing the primary ternary alloy plating layer by frictional heat generation at the time of drawing. While forming an alloy plating layer, the thickness of the outer copper plating layer is a thickness at which the remaining outer copper plating layer other than the outer copper plating layer thermally diffused by the frictional heat generated by the drawing is lost. It is characterized by that.
[0011]
According to a second aspect of the invention, the outer copper plating layer has a thickness of 0.001 μm or more and 0.10 μm or less.
[0012]
According to a third aspect of the present invention, the outer copper plating layer has a thickness of 0.005 μm or more and less than 0.02 μm.
[0013]
The invention of a metal cord according to claim 5 is characterized in that a metal wire manufactured by the manufacturing method according to any one of claims 1 to 3 is used.
[0014]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, an embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a process diagram conceptually illustrating the method for producing a metal wire of the present invention.
In FIG. 1, the manufacturing method of a metal wire is as follows:
(1) A primary ternary alloy plating with an average composition of 60 to 75% by weight of copper and 4 to 14% by weight of nickel by thermally diffusing a plated layer made of copper, zinc and nickel on the surface of the metal wire 2 The step S1 of forming the layer 3;
(2) Step S2 of forming the copper plating layer 4 outside the primary ternary alloy plating layer 3;
(3) The metal wire 2 on which the outer copper plating layer 4 is formed is pulled out with a die 5, and the primary ternary alloy plating layer 3 and the outer copper plating layer 4 are thermally diffused by the frictional heat generated at that time to obtain a secondary. And a wire drawing step S3 for forming the ternary alloy plating layer 6 of the above.
[0015]
More specifically, in the step S1, a conventional diffusion plating method is used. That is, in this example, first, the metal wire 2 is immersed in a copper plating bath, a galvanizing bath, and a nickel plating bath and plated, and as shown conceptually in FIG. The copper plating layer 3A, the zinc plating layer 3B, and the nickel plating layer 3C are formed. Thereafter, the metal wire 2 is heated (for example, about 420 ° C.) by a heating device, and the copper plating layer 3A, the zinc plating layer 3B, and the nickel plating layer 3C are thermally diffused to form a primary ternary alloy plating layer 3. Form.
[0016]
There are copper pyrophosphate and copper sulfate baths as copper plating baths, zinc sulfate baths as zinc plating baths, nickel sulfate baths as nickel plating baths, and heating devices such as current heating devices, high frequency heating devices, flow There is a layer heating furnace.
In addition, in order to obtain a ternary alloy plating layer, “nickel plating → zinc plating → copper plating”, “copper plating → zinc / nickel binary alloy plating”, or “zinc / nickel binary alloy plating → copper”. A method of performing thermal diffusion after multilayer plating by “plating” is preferable.
[0017]
The important thing in the primary ternary alloy plating layer 3 is that the copper content K1 ( % by weight ) in the plating layer is 60 to 75 % by weight (hereinafter sometimes simply referred to as%) , and the nickel content The amount K2 is regulated to 4 to 14%.
[0018]
That is, if it is out of the above range, the effect of the present invention, that is, excellent initial adhesiveness and wet heat adhesiveness can be exhibited while reducing or eliminating the use of organic acid cobalt salt and the like, and wire drawing workability is improved. It is no longer possible to achieve the effect of being able to do so.
[0019]
In particular, when the copper content is greater than 75%, the reaction between the copper in the plating and the sulfur in the rubber excessively progresses during tire vulcanization, and the moisture and heat resistance and heat resistance are significantly reduced. Thus, when the copper content is less than 60%, the reaction between copper in plating and sulfur in rubber is insufficient, and the initial adhesiveness is lowered.
[0020]
Also, when the nickel content is less than 4%, the initial adhesiveness is good, but the effect of improving heat resistance and moist heat resistance is lost, and when the nickel content is greater than 14%, the initial adhesion is good. Adverse effects on adhesion.
[0021]
From such a viewpoint, the copper content is set to 60 to 75% and the nickel content is set to 4 to 14%.
[0022]
Next, in step S2, as conceptually shown in FIG. 3, a copper plating layer 4 is formed outside the primary ternary alloy plating layer 3 obtained by the thermal diffusion treatment. The copper plating layer 4 is formed by electroplating in a copper plating bath such as a copper pyrophosphate bath or a copper sulfate bath, similarly to the copper plating layer 3A. In the thermal diffusion treatment, the surface of the ternary alloy plating layer 3 is oxidized by heating. Therefore, prior to the step S2, for example, etching is performed by immersing in dilute sulfuric acid to remove the oxide film.
[0023]
Next, in the wire drawing step S3, as shown in FIG. 4, the metal wire 2 on which the outer copper plating layer 4 is formed is pulled out of the die 5 and subjected to wire drawing.
[0024]
In practice, a plurality of (for example, eight) dies 5 are used, and wire drawing is performed in multiple stages until the metal wire has a final finished dimension. The secondary ternary alloy plating layer 6 is formed by thermally diffusing the primary ternary alloy plating layer 3 and the outer copper plating layer 4 by the frictional heat generated at the time of drawing.
[0025]
Here, since copper is excellent in ductility, even when the plastic deformation ability of the primary ternary alloy plating layer 3 is low, the slipperiness is improved by the outer copper plating layer 4, and the wire drawing process at the initial stage of wire drawing is achieved. Is possible.
[0026]
Further, due to the frictional heat generated at this time, thermal diffusion occurs between the outer copper plating layer 4 and the primary ternary alloy plating layer 3, and with the progress of this thermal diffusion, the outer copper plating layer 4 and the primary ternary ternary. The alloy plating layer 3 is sequentially replaced with a secondary ternary alloy plating layer 6 around the interface J, as exaggeratedly shown in FIG.
[0027]
The secondary ternary alloy plating layer 6 has a gradient distribution in which the copper content increases from K1 to 100% toward the outer surface side in a transient state of thermal diffusion, that is, in the middle of wire drawing. Therefore, the secondary ternary alloy plating layer 6 can include a region 6Y in which the copper content is higher than the reference line L of 63%, for example, and this region 6Y is superior to the reference line L. The plastic deformation ability, that is, the wire drawing workability can be exhibited.
[0028]
In addition, the secondary ternary alloy plating layer 6 disappears from the high copper ratio side portion due to wear of the drawn wire as the drawing process proceeds, so the copper content is homogenized in a gradually decreasing direction. At the end of the wire drawing process, the copper content K1a is larger than K1 but smaller than the reference line L. As a result, the initial adhesion and wet heat adhesion in the secondary ternary alloy plating layer 6 can be maintained at substantially the same level as the initial adhesion and wet heat adhesion in the primary ternary alloy plating layer 3. It becomes possible.
[0029]
Thus, in the production method of the present invention, the advantages of the primary ternary alloy plating layer 3, that is, excellent initial adhesiveness and wet heat adhesiveness are exhibited while reducing or eliminating the use of organic acid cobalt salts and the like. The wire drawing workability can be improved while ensuring the advantage of being able to be obtained.
[0030]
However, for that purpose, in the outer copper plating layer 4, the remaining copper plating layer portion 4A (shown in FIG. 5) other than the thermally diffused portion is substantially lost due to the wear of the wire drawing at the end of the wire drawing. It is important that In addition, it may disappear during the wire drawing process, that is, before the end.
[0031]
This is because if the copper plating layer portion 4A remains even after the end of the wire drawing process, the sulfide formed at the interface with the rubber becomes excessive at the time of vulcanization, and not only wet heat adhesion but also initial adhesion It is because it will greatly inhibit. Further, even if the remaining copper plating layer portion 4A changes to a ternary alloy due to diffusion due to residual heat, the copper content in the ternary alloy is not uniform and is large on the outer surface side. In such a case, excellent wet heat adhesion cannot be obtained.
[0032]
Therefore, the thickness T (shown in FIG. 3) of the outer copper plating layer 4 is preferably 0.001 μm or more and 0.10 μm or less. If it is less than 0.001 μm, it is too thin to exhibit the effect of improving the wire drawing process, and if it is more than 0.10 μm, there is a possibility that the copper plating layer portion 4A remains too thick. Therefore, in order to sufficiently and reliably achieve both the wire drawing and wet heat adhesion effects, the thickness T is more preferably 0.005 μm or more and less than 0.02 μm.
[0033]
In addition, a metal cord formed by using a metal wire after drawing formed by such a manufacturing method is excellent in adhesive strength with rubber, in particular wet heat adhesive strength, and therefore used in harsh environments such as tire cords. It can employ | adopt suitably. As the metal cord, a single wire cord made of one of the metal wires and a multi-wire cord in which a plurality of metal wires are bundled without twisting or twisted together can be adopted.
[0034]
In addition, this invention can be suitably employ | adopted for the conventional wire drawing of 90 to 98% of area reduction.
[0035]
As mentioned above, although especially preferable embodiment of this invention was explained in full detail, this invention is not limited to embodiment of illustration, It can deform | transform and implement in a various aspect.
[0036]
【Example】
A metal wire having a diameter of 1.25 mm is plated in a copper pyrophosphate bath to form a copper plated layer, then plated in a zinc sulfate bath to form a galvanized layer, and then plated in a nickel sulfate bath. After forming a nickel plating layer, a heat diffusion treatment was performed in a diffusion furnace to form a primary ternary alloy plating layer of copper, zinc, and nickel. Thereafter, this metal wire was immersed in dilute sulfuric acid to etch the oxide layer on the surface. In Examples 1 to 3 and Comparative Examples 2 and 3, the metal wire was further plated in a copper pyrophosphate bath to form an outer copper plating layer on the primary ternary alloy plating layer. Table 1 shows the ratio of copper, zinc and nickel in the primary ternary alloy plating layer and the thickness of the outer copper plating layer.
[0037]
These metal wires were drawn (diameter reduction: 95.3%) to a diameter of 0.27 mm using a cemented carbide die.
[0038]
The drawability at that time was evaluated by an index with the drawing dose of Comparative Example 1 as 100. The larger the value, the better the wire drawing workability.
[0039]
The drawn metal wire was twisted to create a 1 × 3 metal cord. This metal cord is sandwiched between rubber sheets having the composition shown in Table 2 and vulcanized by heating to prepare a sample for wet heat bonding, and the initial adhesiveness of this sample, temperature 80 ° C., humidity 95% (relative humidity) The wet heat adhesion after being left in the oven for 5 days was tested. The evaluation criteria are as follows.
5 --- Completely covered with rubber, the plated surface of the metal cord is not visible.
4 --- Three to six plating surfaces are visible.
3 --- Thirteen to twenty places of plated surface are visible.
2 --- 21 or more plated surfaces can be seen, but 60% or more are covered with rubber as a whole.
1 --- The portion covered with rubber is less than 30%.
[0040]
[Table 1]

[0041]
[Table 2]

[0042]
【The invention's effect】
Since the present invention is configured as described above, even when ternary alloy plating is used, it is possible to prevent a decrease in wire drawing workability, while reducing or eliminating the use of organic acid cobalt salt, etc. In addition to exerting initial adhesiveness and wet heat adhesiveness, wire drawing processability can be improved.
[Brief description of the drawings]
FIG. 1 is a process chart conceptually illustrating a method for producing a metal wire according to the present invention.
FIG. 2 is a diagram for explaining a process of forming a primary ternary alloy plating layer.
FIG. 3 is a cross-sectional view showing a copper plating layer formed outside the primary ternary alloy plating layer.
FIG. 4 is a cross-sectional view showing wire drawing.
FIG. 5 is a diagram showing a distribution state of copper in thermal diffusion by wire drawing.
[Explanation of symbols]
2 Metal wire 3 Primary ternary alloy plating layer 3A Copper plating layer 3B Zinc plating layer 3C Nickel plating layer 4 Outer copper plating layer 5 Die 6 Secondary ternary alloy plating layer

Claims (4)

A step of thermally diffusing a plated layer made of copper, zinc and nickel on the surface of a metal wire to form a primary ternary alloy plated layer having an average composition of 60 to 75% by weight of copper and 4 to 14% by weight of nickel When,
And forming a copper plating layer outside the primary ternary alloy plating layer,
The metal wire on which the outer copper plating layer is formed is pulled out with a die, and a secondary ternary is formed by the primary ternary alloy plating layer and the outer copper plating layer facing the primary ternary alloy plating layer by frictional heat generation at the time of drawing. While forming the alloy plating layer, the thickness of the outer copper plating layer is such that the remaining outer copper plating layer other than the outer copper plating layer thermally diffused by the frictional heat generated by the drawing disappears. A method for producing a metal wire, characterized by comprising: 2. The method of manufacturing a metal wire according to claim 1, wherein the outer copper plating layer has a thickness of 0.001 μm or more and 0.10 μm or less.   3. The method of manufacturing a metal wire according to claim 1, wherein the outer copper plating layer has a thickness of 0.005 μm or more and less than 0.02 μm.   A metal cord using a metal wire manufactured by the manufacturing method according to claim 1.

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